3D numerical modelling of interception efficiency of grate inlets with supercritical surface flow

Within the presented study 3D numerical model runs of grate inlets with supercritical surface flow conditions are done with the aim of expanding the knowledge of the street grate inlet capacity and the flow conditions that occur. Information of interaction processes from street to sewer are necessary to build up 1D/2D dual drainage models in order to get realistic information about urban flooding in case of intense rainfall events. Validation of the 3D model is done by use of laboratory results. The surface flow approaching the grate inlet with high flow velocities and small water depths can be simulated with good accordance to the measured results from laboratory. Major deviations occur in the intercepted flow rate and the water flowing over the grate. The analysis of the results allows the assumption that the deviations are probably caused by an insufficient calculation geometry.